Copper accumulation by the root and leaf biomass of Salvinia natans (L.) All. (Salviniaceae)

Abstract

Aquatic plants are often exposed to metal contamination. The study evaluated the bioaccumulation of copper (Cu) ions in aqueous solution by the biomass of leaves and roots of the macrophyte Salvinia natans. Plants of S. natans were submitted to culture solutions with different concentrations of Cu ions, evaluated at intervals of seven days. The leaf and root samples were separately subjected to atomic absorption spectroscopy with flame atomization to assess the concentration of copper accumulated in its biomass. The results demonstrated a pattern of accumulation dependent on the concentration of the metal in the culture medium and the time of exposure of the plants to the contamination. The accumulation was greater in the biomass of the roots when compared to the leaves. Throughout the experiment, toxicity symptoms were observed in the morphology of plants subjected to all copper concentrations, demonstrating the macrophyte's viability for bioindicating the toxicity of this metal in aquatic environments. A high accumulation of copper ions was obtained both in the biomass of the roots and leaves of the plants, confirming their potential bioaccumulator of Cu. The analysis of biomass suggests an important characteristic of metal compartmentalization by the plant, associating the absorption by the roots and the possible transfer to the leaves. In general, our results show that S. natans is an organism with a potential bioindicator and bioaccumulator of Cu and consists of a viable cost-effective option for phytoremediation of aquatic environments contaminated by metals